The invention relates to telephone systems and more particularly to a system and method for charging wireless telephone subscribers for their telephone usage from a subscriber account. In particular, it pertains to a system and method for charging wireless telephone users in real time from a pre-paid account and immediately terminating or restricting their calls when the account balance is depleted.
Long distance service companies and wireless telephone companies typically bill their subscribers based on actual calls placed and the duration of those calls. Since unpredictable calling patterns make the total charge for these services unpredictable, they are typically billed to the subscribers at regular intervals after such calls have been made. However, some subscribers are denied this privilege due to their inadequate credit rating. Alternately, some subscribers prefer to control telephone usage by members of their families or others, by limiting calls to a predetermined total cost. It is desirable to be able to provide wireless telephone services for these situations, while reducing exposure to bad debt for the wireless telephone service providers, and reducing exposure to excessive charges for the subscribers. One solution to this problem is to provide pre-paid accounts for wireless telephone service. As telephone charges accrue, they are simply deducted from these accounts. If the subscriber does not maintain an adequate balance, then the wireless telephone services can be wholly or partially disabled or cut off, thereby reducing the financial risk inherent in unrestricted telephone usage.
Two basic strategies are used to provide such pre-paid accounts. The first approach monitors billing records and compares the records with an account balance to determine when the account balance has been depleted, referred to as xe2x80x9cHotbillingxe2x80x9d.
However, these comparisons are usually made after each phone calls has been completed. The delay between accrual of the telephone service charges and the reduction of the account balance allows subscribers to significantly overrun their account balance during a call. As a result, prepaid subscribers in this type of system may create negative account balances before the service provider detects the overrun and phone service is terminated or blocked. The financial risk for this type of billing system increases as the interval between charge accrual and account reconciliation increases.
An alternative approach provides for trunk-looping the voice channel for prepaid calls through a device that monitors individual calls and calculates costs in real-time. However, this type of system requires the voice channel to be rerouted through the monitoring device, which may be located a great distance away. This rerouting may require a great deal of additional network capacity, and is therefore very expensive for the telephone companies to implement.
An additional limitation of prior art trunk-looping systems is the inability to use such systems when roaming. In the prior art, prepaid calls are routed through a monitoring device that is connected to the calling device""s home switch. When the calling device is roaming, the roaming area switch is not connected to the prepaid monitoring device, and, therefore, is unable to provide prepaid service to the caller.
The prior art systems and methods for providing prepaid wireless telephone service have obvious disadvantages. Service providers resist implementing either one due to perceived high costs and/or financial risk due to delayed processing.
The instant invention solves the aforementioned problems by monitoring the presence of a subscriber""s wireless telephone call, determining the accrued cost of the call, and appropriately reducing the account balance, all as the call is taking place. It does so without rerouting voice traffic and can be implemented in an existing mobile switching center (MSC). The invention takes advantage of the MSC""s capability to process call handling instructions from an Signaling Control Point (SCP) and to connect an Interactive Voice Response (WR) unit to a call in progress. Based on a predetermined minimum account threshold, the system has the capability of mailing a warning announcement to the subscriber whenever the threshold is being approached, disconnecting the call when the threshold is reached, and preventing further calls until the account balance has been replenished. Other options are also available, such as restricting telephone calls to/from certain telephone numbers, certain calling zones, or certain geographical boundaries.
Replenishment of the account can be accomplished by the subscriber through the use of standard cash, check, or money order payments, through pre-authorized credit card payments, or through the purchase of debit cards from authorized distributors.
A preferred embodiment of the invention is implemented in software in a computer system which can be integrated into existing telephone communications systems for wireless telephones, including cellular and PCS telephones. The present invention is directed to a system and method for communicating the status of a call between the switching system and pre-paid control system. Protocols between the switch and the pre-paid system define specific command and response codes, which are communicated between the various components to permit specific activities to occur across a distributed network. Each of the command and response codes can include various parameters. The instant invention uses additional commands, responses, and parameters within an existing protocol to signal between the switching system and the pre-paid control system to effect network based prepaid service.
One technical advantage of the invention is a system that can monitor the status of calls and adjust the associated account balance in real time so that service can be modified or terminated immediately whenever the funds in the pre-paid account are depleted.
Another advantage is that this monitoring is provided without causing the voice channel to be rerouted from its normal path.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram of a wireless prepaid system employing the present invention;
FIG. 2 is a flowchart illustrating subscriber registration in an illustrative example of the present invention;
FIG. 3 is a flowchart illustrating call origination in an illustrative example of the present invention;
FIG. 4 is a flowchart illustrating how warning announcements are played in an illustrative example of the present invention;
FIG. 5 is a flowchart illustrating how the illustrative example of the present invention operates when the subscriber exhaust the prepaid account balance;
FIG. 6 is a flowchart illustrating call delivery in an illustrative example of the present invention;
FIG. 7 is a flowchart illustrating error handling in an illustrative example of the present invention;
FIG. 8 is a flowchart illustrating fraud prevention in an illustrative example of the present invention; and
FIG. 9 is a block diagram of a prior art prepaid wireless system.